PSI - Issue 68

Shiyu Suzuki et al. / Procedia Structural Integrity 68 (2025) 596–602 S. Suzuku, N. Tsushima / Structural Integrity Procedia 00 (2025) 000–000

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monotonically decreases with an increase in the temperature. Thus, the high cycle fatigue lives longer at 200 °C than at RT may be a unique characteristic of the lattice structure employed in this study.

Fig. 5. (a) SN diagram at 200 °C and RT; (b) Load-displacement curves at the half life, N f /2, at 200 °C.

Fig. 6. Optical observations after fracture in fatigue tests at 200 °C.

4. Conclusion This study investigated the effect of temperature on the tensile and fatigue properties of AlSi10Mg lattice structures fabricated by additive manufacturing. Two types of specimens, namely, cylindrical specimens and lattice specimens, were manufactured by the laser powder bed fusion (L-PBF). Static tensile tests of the lattice specimens were performed at -60 °C, RT and 200 °C while fatigue tests of the lattice and cylindrical specimens were performed at RT and 200 °C. The following results were obtained: • In the static tensile tests of the lattice specimens, decreasing temperature from RT to -60 °C resulted in a higher strength and an equivalent ductility whereas increasing temperature from RT to 200 °C resulted in a lower strength and a higher ductility. • In the fatigue tests of the lattice specimens at RT, macroscopically, the elastic deformation was dominant in the lattice specimens under all load conditions, and Basquin’s law can be successfully applied. Single main cracks propagated and resulted in the fracture under all of the load conditions as similar to the static tensile test. Each strut was fractured at points of intersections with other struts. The fatigue life of the lattice specimens was less than one tenth of that of the cylindrical specimens. This was attributed to the stress concentration in the lattice structures due to their geometries. • In the fatigue tests at 200 °C, although the load-displacement curves were linear in all of the load conditions, the specimen was fractured being accompanied by a certain amount of the plastic deformation only under the highest